If its a V6 it will be the rear main seal and sump gasket.
I got my rear main done 2 years ago it cost me $500 in labor,
Its not just the seal you'll will have to buy, There is a aluminum housing that the seal gets pressed into, they warp and start leaking also.
From memory its about $120
The Red arrows are pointing to the worst design I have ever see..
It looks like the aluminum housing fits perfectly into the cast iron engine block But it doesn't So you'll need a good sump gasket Because there will be a gap between the aluminum housing and the engine block where the sump gasket sits. (I should of taken a photo it)
A sump gasket is about 20mm wide, on my one were the arrows are pointing I had about 2-3mm on each side were the aluminum housing and engine block was touching to get a good seal (its still leaking to this day)
I hate oil leaks, But its a lot of work to fits and its a A-hole of a job and Its a lot of money for a leak that will probably come back due to a crap design